Building a pair of Linkwitz Orion v.3.x.x speakers kept me busy all through April this year. I had bought parts all the way back in 2007. Talk about procrastination! The project was much more difficult than I'd first thought. Between cutting the multiple curves on the plywood, the no-screws midrange mounting (to prevent transfer of vibrations into the baffle), sourcing odd parts, the painting, multiple layers of clear-coat, endless sanding, & finally wiring 8 thick cables to 8-conductor Speakon plugs & jacks -- it took me over a month working nearly full time! Admittedly, I'm not an expert woodworker, and I did want the end result to look good. The most elaborate & complex audio DIY project I've done -- even though I was working from plans and a guide. There are lots of details that need to be finessed. I'm pretty happy with the end result, both visual & aural.

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My experience with these speakers (version "+" w/ Linkwitz supplied electronic xover) has gone something like this:1) excitement & relief at finally completing the damn things & hearing them at last!2) delight at the big sound, obviously broad bandwidth, and great dynamics -- combined with dismay at an oddly "horny" midband (vocals, etc), heavy midbass3) extended fine-tuning with positioning & active crossover driver levels resulting in much better tonal balance -- but still feeling the need to tweak JRiver EQ controls to compensate for better/worse recordings (especially the worse ones as the speakers seemed mercilessly revealing)4) room acoustics compensation applied with software & multiple freq response tests at seated position with lab quality mic & associated gear...5) ...resulting now in just about the best canned music I've heard in 40+ years of high end hifi experience. Extremely transparent, tonally accurate, very dynamic, not just a window to the music but an open garage door. I rarely feel the need to adjust tonal balance for bad or odd recordings now.

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You do not have the required permissions to view the files attached to this post._________________Mike Chin, SPCR Editor/PublisherSupport SPCR by buying your gear through these links: MSI R9 280X Gaming 3G for $189!, Amazon and Newegg

They look pretty awesome! Both the drivers and the workmanship on the wood parts. I am surprised at the open bass enclosures. I was anticipating a horn loaded bass setup, or sealed. What is the tweeter?

Am I reading the frequency graph right - they are about 5dB down at 25Hz? That is great!

Tweeters are nearly $300 each, part of Seas Millenium series. Mids are magnesium cone 8" also near $300 each. Woofers are quite massive, 10" Nomex cone. The whole driver package cost close to $2500 w/ discount, shipping, taxes... iirc. Xover was something like $800 back then, and the 8-ch Rotel was over a grand. I want to swap the Rotel (40w/ch @8ohms, 65@4...) for something with more power. Each bass driver gets a single amp channel -- but I don't think it is enough to sustain high enough volume for me in my space because there's a lot of boost in the xover to compensate for the bass front/back wave cancellation. I'm probably doing to assemble a multi-ch amp using one of the many class D modules out there. They are so small and efficient & sound fine to me; I made a couple amps with such modules already. I priced one out: 200w/ch @8 ohms, 8 ch: Around $600 for modules + PSU. I could strip a Hush ATX PC I have on hand and use it o house the amp; the heatsinks would be enough to cool it.

The spkr design is best described as a wide-bandwidth, open baffle dipole -- it tries to disperse the sound in same arc both front and back, and because the back wave is in reverse phase, there is a 6 dB null to the side -- even in the bass -- and cancellation occurs at lower frequencies. Hence the need for bass compensation boost.

This is the first open baffle speaker I've built & I'm sold on the concept. The sound -- including the bass -- seems so unfettered & easy compared to almost all the other speakers I've heard. There's such naturalness in the bass. A huge difference is the simple fact that there's no enclosure of the back wave, no high pressure in a box that's trying to resonate in all kinds of different ways. Most high end speakers' bass sound overly damped in comparison (assuming my memory serves correctly).

I think these speakers could be built with acrylic panels and sound the same -- and look pretty cool. I have a vague idea to make another pair of cabinets out of clear acrylic with wood only for the curved side panels.

I actually "built" a center channel speaker for my TV room -- a 1.5' x 1' x 3/4" plywood board, with a single 7" high quality driver mounted in the center. Open back. It's transformed the sound in there, I'm completely unconscious of the audio system when watching videos... the sound doesn't distract at all from the video, which is the way it should be.

Wow, that's quite the enclosure! No way to cut those boards so clean without.... a bandsaw? w/ template?

Actually, hornloading is very different from what is done in the Orion. A horn is something of a "step-up" transformer -- it actually accelerates the wave and makes the speaker a lot more efficient in a broad frequency band (but not the entire audible band) than w/o the horn. Much less cone excursion is required for a given SPL compared to other speaker "enclosures". It also still "loads" the cone -- there's still some air pressure on the cone. The open baffle, in contrast, is a derivative of the infinite baffle, where a driver was mounted on a very large area board. The basic idea was to eliminate the back wave without putting pressure on the cone (which always happens when you put the drive in a box -- unless it is a really huge box, like a small room). As rooms got smaller (let's face it, audio began as a hobby for the rich who had huge houses & huge rooms), infinite baffles fell out of favor.

With the rise of planar speakers like Magnepans and electrostatics, the idea of open baffle speakers arose again. A side benefit was the reflected back wave, which provides much greater illusion of depth with a stereo recording than front-only firing speakers. This automatically means the baffle can't be huge, but then you have to deal with the bass cancellation from the back wave. Only the availability of cheap high amplifier power & electronic equalization to compensate for the bass cancellation makes open baffle speakers workable... which is when relatively small, open baffle, dipole speakers with dynamic drivers began to arise. That's in the past 20 years only.

Unlike horn loaded speakers, the bass drivers in an open baffle dipole need very high cone excursions to produce any real volume in the deeper bass. All things being equal, a horn-loaded bass driver will have considerably lower harmonic distortion as a result. The horn has controlled directivity, but only fires into a hemisphere, it is more or less cardioid; the open baffle dipole has a figure 8 pattern, with it at the center point of the 8.

I've tried dipoles in my listening room, but with mixed results. I love the airiness that they often afford, but their placement is very tricky and sound staging tends to suffer. The require extra attention to not only placement, but room treatment. Just too finicky for my tastes.

It's a 3-way electronic xover with custom eq designed specifically for these spkrs. 24db/oct 120 & 1500Hz, iirc. Amp is 8-ch 40W/ch Rotel (probably the weak link). The 2 tweets in each spkr get fed by one ch, the mid by another, and each bass driver gets its own amp ch. So supposedly 160W/ spkr -- but I could easily use 400W/spkr w/o any real danger of overload, methinks. I'd certainly like to have more power -- not to play much louder but to keep the amps cruising at high volume because I think some edginess creeps in now due to subtle (or not so subtle) momentary clipping.

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I've tried dipoles in my listening room, but with mixed results. I love the airiness that they often afford, but their placement is very tricky and sound staging tends to suffer. The require extra attention to not only placement, but room treatment. Just too finicky for my tastes.

My room is completely untreated. But I have software compensation for room acoustics, which definitely helps. The most obvious difference with compensation is a bass boominess ~100Hz (always been there in this room) that goes away, and a shoutiness in the vocal range which is nicely tamed.

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